Easy opening container



1970 H. s. RUEKBERG 3,

EASY OPENING CONTAINER Filed Sept. 20, 1968 INVENTOF? HERBERT s. RUEKBRG ATT' Y.

United States Patent 3,532,248 EASY OPENING CONTAINER Herbert S.Ruekberg, Highland Park, Ill., assignor to Continental Can Company,Inc., New York, N.Y., a corporation of New York Filed Sept. 20, 1968,Ser. No. 761,185 Int. Cl. B65d 17/00, 17/20, 17/24 US. Cl. 220-54 3Claims ABSTRACT OF THE DISCLOSURE An easy opening plastic closure for acontainer which includes a panel attachable to the container and aremovable panel portion separable from the panel to provide an openingtherein. The removable panel is defined by a weakening line including athinned wall section of lesser thickness than the remainder of the panelso that the removable panel portion is severable therealong upon beingstressed. A finger grip means is attached to the removable panel portionadjacent the weakening line. The finger grip means is tiltable andincludes a rigid portion which engages the attachment panel upon beingtilted so that the thinned wall section is subjected to a localizedconcentrated stress causing the weakening line to be severed. Theremovable panel portion is thereafter separated from the panel along thefull length of the weakening line by means of a pulling force applied onthe finger grip means.

I BACKGROUND OF THE INVENTION The present invention relates to easyopening containers and, more particularly, to a plastic easy openingclosure for the containers and the like.

Plastic easy opening closures of the type to which the present inventionrelates are generally formed by moulding to provide a panel having aremovable panel portion. The closure panel is suitably fixed about anopening provided in a container.

The removable panel portion is defined by a weakening line which iscreated by thinning the panel wall. The thinned wall may be formedeither during molding of the closure unit or by scoring or the like toreduce the thickness of the panel. Finger grip means joins the removablepanel portion at a point adjacent the weakening line for applying apulling force to sever the panel along the weakening line. To achieve aproperly functioning plastic easy opening structure or closure, thereare two factors which must be considered. These factors relate directlyto the weakening line structure.

Firstly, the weakening line must be sufficiently strong to maintain theintegrity of the package before opening. For example, theweakening lineshould be capable of assuming the pressure forces exerted thereon by theproduct, such as carbonated beverages, contained in the containerwithout rupturing. At the same time the weakening line must besutficiently weak to permit easy tearing when the removable panel is tobe removed. Preferably, the forces should be less than about pounds.

The second consideration relates to the initial tearing of the removablepanel from the panel. The tearing of the weakening line occurs as aresult of the failure of the weakening line in tension. As is known,plastic materials from which the closures are formed generally have ahigh tensile strength so that the pulling force applied at the point ofattachment is distributed along the total length of the weakening line.This condition requires that a high pulling force be applied to initiatethe tear. To create a sufiiciently high tensile force to sever theweakening line having the required sealing characteristics, usuallyrequires a high pulling force in 3,532,248 Patented Oct. 6, 1970 ICCexcess of the 15 pounds mentioned above. However, after the tear hasbeen initiated, considerable less pull or force is required to completethe separation.

To achieve the initial tear or separation of the weakening line with aminimum amount of pull on the finger grip, the pulling force should beapplied in a manner so that the separating forces are concentrated in alocalized area.

If the initial tear is to be achieved by a tensile stress in a localizedarea by solely an upwardly directed pull on the finger grip, it would benecessary to attach the finger grip to the removable panel portion witha very small cross-sectional area. However, when the finger grip isattached with a small cross-sectional area, the crosssectional area isso weak that the pull tab separates from the removable panel prior toseverance of the weakening line. -If the cross-sectional area is madelarger, a greater length of the weakening line assumes the forces sothat a greater pulling force must be applied thereby making it moredifii cult to initiate the tear in the score.

SUMMARY OF THE INVENTION By the present invention it is proposed toprovide a plastic closure structure which overcomes the difficultiesencountered heretofore in connection with the separation of theremovable panel portion from the panel.

This is accomplished generally by the provision of a finger grip whichis mounted on the removable panel portion for tilting movement andincludes a rigid member which, upon tilting the finger grip, engages theattachment panel opposite the point of joining of the finger grip to theremovable panel portion and applies localized concentrated forces on theweakening line so as to rupture the latter.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of acontainer showing the easy opening plastic closure embodying theprinciples of the present invention attached thereto;

FIG. 2 is a fragmentary view of the easy opening closure of FIG. 1 andshowing, in particular, the finger grip and stress applying arrangement;

FIG. 3 is a cros-sectional view taken generally along the lines 33 ofFIG. 1;

FIG. 4 is an end view of the finger grip and stress applying arrangementtaken generally along the lines 4-4 of FIG. 3; and

FIG. 5 is a cross-sectional view showing the position of the finger gripand localized stress applying ar- 1rangement during the initial tearingof the weakening DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring nowto the drawings, the closure 10 embodying the principles of the presentinvention is shown applied to a container 11 comprising generally acontainer body 12 which may be of generally cylindrical configurationhaving a bottom closure (not shown). The container body 12 may be formedof any suitable material such as metal, composition board such ascanboard and the like, plastic or any suitable rigid material. The upperend of the container body 12 may be formed with an outwardly projectingflange 14 to which the easy opening closure 10 may be suitably bonded asby an adhesive, spin-welding or the like.

The easy opening closure 10 is made from plastic and may be formed byinjection molding or the like. The closure 10 includes an attachmentpanel 16 having a marginal portion overlying and bonded to the flange 14of the container body 12. A removable panel 17, as shown, is depressedor vertically spaced below the attachment panel 16 and is joined theretoby a continuous vertical wall 18 of substantially lesser thickness thaneither the attachment panel 16 or removable panel 17 to define aweakening line. The thinned wall 18 may be molded to impart the samestructural bond characteristics thereto as the remaining closurestructure or be molded to provide a Weld line having lesser bondcharacteristics, as more fully explained in my co-pending US. patentapplication S.N. 719,503 filed Apr. 8, 1968, to which reference is madefor a more detailed description. While the weakening line is shown as avertical wall, it should be clearly understood that the weakening lineor thinned wall 18 may also be disposed horizontally with the attachmentpanel 16 and removable panel 17 in horizontal alignment or verticallydisplaced relatively to each other.

Moreover, the weakening line 18 may be continuous as shown so that theremovable panel 18 is completely separable or it may be formed withspaced ends so as to be only partially removable from the attachmentpanel 16. It should be readily apparent that the attachment panel 16 andremovable panel 17 may be formed of any desired shape, and that closuremaybe adapted for use with container structures other than the containerend struc ture illustrated.

Extending upwardly from the removable panel 17 adjacent the weakeningline 18 is a finger grip portion or pull tab 19 comprising generally afinger grip panel 20 which may be of substantially rectangular outlinealthough any other suitable configuration such as a ring may be used.Integrally connecting the finger grip panel 20 with the removable panel17 is a downwardly extending flange or post 21. The post 21 may bearcuate and concentric with the circular weakening line 18 and extendfor the full width of the finger grip portion 19.

Formed on the upper side of the finger grip portion 19 is an upstandingridge 22 which terminates in alignment with the outer face of theattachment flange 21. The ridge 22 is formed with a recess 23 whichaccommodates therein an upstanding lug 24 formed integral with theattachment panel 16 on the opposite side of the weakening line 18. Thelug 24 is disposed in close proximity to the weakening line 18 and maybe substantially conical in its upper end so as to lie flush against theface of the indentation 23 on the ridge 22 as shown in FIG. 5.

To separate the removable panel 17 from the attachment panel 16, thefinger grip portion 19 is tilted about the post 21 as shown in FIG. 5,so that the ridge 22 engages the lug 24. This action causes the lug 24to be displaced downwardly and to the left and the adjacent outer edgeof the removable panel 17 to be displaced in substantially the oppositedirection. This causes the stresses to be concentrated on the length ofthe weakening line 18 disposed between the line of attachment of the lug24 to the attachment panel 16 and the line of attachment of the fingergrip post 21 to the removable panel 17. As illustrated, this length ofthe weakening line 18 is substantially equal to the diameter of the lug24 which is of relatively small diameter so that the stresses areconcentrated in only a small increment of the total length of theweakening line 18. In this manner the force required to initiate therupture in this relatively small area is considerably less than thatrequires to sever the full length thereof.

After the initial separation of the weakening line 18 by the applicationof the concentrated stress, the finger grip portion 19 is pulledupwardly so that the remainder of the removable panel 17 may beseparated from the attachment panel 16.

It is to be noted that the finger grip portion 19 is joined to theremovable panel 17 on a relatively large cross-sectional area of thepost 21, so that the stresses imposed thereon during the application ofthe stretching of the weakening line 18 are distributed over this largearea. In this manner the possibility of separating the finger gripportion 19 from the removable panel 17 is minimized.

I claim:

1. An easy opening molded plastic closure for a container, said closurecomprising an attachment panel adapted to be attached to the containerand having a thinned wall section forming a weakening line which definesa removable panel portion, said weakening line being of lesser thicknessthan said attachment panel and said removable panel portion, finger gripmeans including attaching means on said removable panel portion along alength thereof and spaced from said weakening line for tilting movement,a narrow upstanding lug on said attachment panel closely adjacent tosaid weakening line, said finger grip portion having an end engageablewith said narrow upstanding lug upon tilting of said finger grip portionabout said attachment means, thereby to create a concentration ofstresses on said weakening line along a line substantially narrower thanthe length of said attaching means whereby said weakening line isinitially severed along said narrow line of stress concentration.

2. The invention as defined in claim 1 wherein said removable panelportion lies in a plane vertically spaced from the remainder of saidattachment panel, and said thinned wall section forming said weakeningline is vertically disposed between the underside of said panel and theupper side of said removable panel portion.

3. The invention as defined in claim 1 wherein said finger grip end isin the form of an upstanding ridge and said ridge includes a recess inwhich said lug is received.

References Cited UNITED STATES PATENTS 3,415,412 12/1968 Robinson et al220-54 3,434,620 381969 Laurizio 22O27 GEORGE T. HALL, Primary ExaminerUS. Cl. X.R. 22027

